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231 Cards in this Set
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Minerals |
1) naturally occurring, solid substances 2) formed by geologic processes, 3) with a definable chemical composition and 4) an internal structure characterized by an orderly arrangement of atoms, ions, or molecules in a crystalline lattice. 5) Most minerals are inorganic. |
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Five Ways to Make a Mineral |
1)Solidification from a melt 2) Precipitation from a solution 3) Solid-state diffusion 4) Biomineralization 5) Precipitation from gas |
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biomineralization |
(aka " the metabolism of organisms") Living organisms cause minerals to precipitate. Biogenic minerals are produced by organisms. The minerals in shells are an example of biomineralization. Marine organisms make shells out of calcite, a calcium carbonate (CaCO3) mineral |
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Solidification from a melt |
a.k.a. "freezing of a liquid to form a solid" Minerals form from the cooling of magma and lava as atoms arrange into orderly patterns. New crystals start as a small collection of atoms (a “seed”). Atoms in the surrounding material attach themselves to thegrowing seed to form a crystal. Crystals maintain their shape during growth until they interfere with each other. crystals are anhedral or euhedral. |
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anhedral crystals |
(poorly-formed); grow in confined spaces. when it hits the boundaries of the confined space, the crystal as a whole no longer reflects its original structure. |
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euhedral crystals |
(well-formed); grow into an open space and can form beautiful crystals because they do not have interruptions/inhibitors (unlike anhedral crystals) |
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Precipitation from a solution |
chemicals dissolved in water bond together when water is removed |
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Solid-state diffusion |
atoms move through a solid and rearrange into a new crystal structure |
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Precipitation from a gas |
Sulfur gases emitted from hydrothermal vents can condense and precipitate to form sulfur minerals |
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How to break a mineral |
By breaking its chemical bonds. Melt it, dissolve it, degrade it with reactive chemicals |
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Six common mineral classification properties |
1) Color
2) Streak 3) Lustre 4) Crystal Habit 5) Hardness 6) Specific gravity also-- magnetism, reactivity with acid, cleavage |
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Specific gravity |
Represents how dense (mass/volume) a mineral is, due to how heavy and closely packed its atoms are |
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Crystal Lattice |
The orderly framework within which the atoms or ions of a mineral are fixed |
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How many different types of mineral are known? |
About 4000-- each with a name and distinctive physicalproperties (such as color, streak, luster, hardness, specific gravity, crystal habit, cleavage,magnetism, and reactivity with acid) |
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How can you identify a mineral? |
By observing the unique physical properties of its chemical composition and crystalstructure.
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Cleavage |
weak planes along which crystals break or fracture // One or more planes with one or more angles |
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Difference between cleavage and crystal faces |
Cleavage planes can be repeated, whereas a crystal face is a single surface. |
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Most convenient way to classify minerals |
grouped by chemical composition |
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Seven mineral classes |
1) silicates 2) oxides 3) sulfides 4) sulfates 5) halides 6) carbonates 7) native metals |
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The crystal structure of which of the seven mineral classes is NOT defined by the anionor anionic group present in the mineral? |
Native metals |
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anion/anionic group |
a negatively charged ion |
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Most common minerals on earth |
Silicate minerals |
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silicon-oxygen tetrahedron |
a silicon atom surrounded by four oxygen atoms which serves as the fundamental building block of silicate minerals. they are arranged in multiple ways to form different types of silicate minerals. forms the backbone of the most abundant class of minerals (silicates) on Earth |
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What determines the ratio of Silicon:Oxygen in the chemical formula? |
The way oxygen atoms are shared |
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Rocks |
collections of minerals |
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Gemstones |
minerals that are considered valuable; can be rare (diamonds) cut and polished forms of common minerals (emeralds, rubies) |
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Magma |
liquid rock (melt) under the Earth’s surface |
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Lava |
melt that has erupted from avolcano at the Earth’s surface |
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When does magma form? Under what three circumstances does this occur? |
when hot rock in the Earth partially melts. Happens only when: 1) pressure decreases, 2) volatiles are added to hot rock, or 3) heat is transferred into the crust by magma rising from the mantle into the crust |
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3 properties of a rock |
1) Coherent – holds together; must be broken apart to separate into smaller pieces 2) Naturally occurring – made by geologic or biologic processes (not man-made) 3) An aggregate (collection) of one or more minerals or a mass of glass |
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Three basic rock types |
Igneous, sedimentary, metamorphic |
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Four magma compositions |
1) felsic (silicic), 2) intermediate, 3) mafic, and 4) ultramafic |
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What does the composition of magma reflect? |
the original composition of the rock from which the magma formed and the way the magma evolves |
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Why does magma rise? |
because of its buoyancy and because of pressure caused by theweight of overlying rock |
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Viscosity |
The resistance of material to flow |
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Which is more viscous-- mafic or felsic magma? |
Felsic |
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Dependent factors of magma rate of cooling |
1) depth of intrusion, 2) the sizeand shape of the magma body, and 3) whether circulating groundwater is present |
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What influences the texture of an igneous rock? |
cooling time |
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How do extrusive igneous rocks form? |
form from lava that erupts out of a volcano |
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How do intrusive igneous rocks form? |
magma intrudes into preexisting rock below Earth’s surface. forms from magma that freezes inside the Earth. |
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Vesicles |
holes formed by bubbles that get trapped in cooling melt |
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Two possible actions of lava |
1) solidify to form flows, or 2) explode into the air to form ash |
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Volcanic Breccia |
pyroclastic rock that contains largerfragments of volcanic debris |
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Tuff |
fine-grained pyroclastic rock composed mostlyof volcanic ash |
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Pyroclastic rock |
rock made from fragments that were blown out of a volcano during an explosion and were then packed or welded together |
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Scoria |
glassy mafic volcanic rock with many vesicles; darker with bigger vesicles than pumice |
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Pumice |
glassy felsic volcanic rock with manysmall vesicles that give it a sponge-like appearance; cools from frothy lava |
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Obsidian |
Solid, mafic volcanic glass |
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Pluton |
an irregular or blob-shaped intrusion; can range in size from tens of m across to tens of km across |
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dikes |
Tabular intrusions that cut across layering Huge intrusions, made up of manyplutons, are known as batholiths. |
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sills |
tabular intrusions that cut parallel to layering |
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batholiths |
Huge intrusions, made up of manyplutons. a vast composite, intrusive, igneous rock body up to several hundred km long and 100 km wide, formed by the intrusion of numerous plutons in the same region |
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What two main factors are used to classify igneous rocks? |
1) texture 2) composition |
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Origin of igneous rocks |
understood in the context of plate tectonics. 1) Magma forms at continental or island volcanic arcs along convergent margins, mostlybecause of the addition of volatiles to the asthenosphere above the subducting slab. 2) Igneousrocks form... a-- at hot spots, owing to the decompression melting of a rising mantle plume. b-- at rifts as a result of either decompression melting of the asthenospherebelow the thinning lithosphere or heat transfer from mantle melts into crustal rocks. c-- along mid- ocean ridges because of decompression melting of the risingasthenosphere |
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Crystalline igneous rocks are identified by... |
1) grain size (fine or coarse) and, 2) composition (felsic or mafic) |
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Where do igneous rocks form? |
Where there is melting... 1) Volcanic arcs along ocean trenches 2) Hot spots 3) Continental rifts 4) Mid-ocean ridges |
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3 major types of sedimentary rocks |
1) shale 2) sandstone 3) limestone |
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How do sedimentary rocks form? |
form from existing materials at or near the Earth’s surface and typically form layers that blanket underlying igneous or metamorphic (“basement”) rocks |
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Four major classes of sedimentary rocks |
1) Clastic 2) Biochemical 3) Chemical 4) Organic |
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Five easy ways to make a clastic rock |
1) Weathering 2) Erosion 3) Transport 4) Deposition 5) Lithification |
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Are sedimentary rocks rare? |
Sediments and sedimentary rocks are rare in the crust as a whole, they are abundant at thesurface |
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Weathering |
bedrock is broken down into fragments or grains by physical and chemical processes |
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Erosion |
Rock is physically separated from its substrate due to wind, water, gravity, or ice |
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Transport |
sediments (loose grains) are moved by gravity, wind, water, or ice |
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Deposition |
sediment settles out of the transport medium (ice/water/wind) |
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Deposition |
sediment settles out of the transport medium (ice/water/wind) |
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Lithification |
sediment is transformed into solid rock due to compaction and cementation |
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Compaction |
Overlying pressure squeezes out water and air and packs grains together |
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Cementation |
Minerals (usually calcite or quartz) crystallize out of groundwater and glue grains together |
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What can the properties of a sedimentary rock reveal? |
its journey from source to depositional environment (where sediment accumulates) |
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Clastic sedimentary rocks |
form fromcemented- together grains that were first produced by weathering, then transported,deposited, and lithified |
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Biochemical sedimentary rocks |
formed from material (such as shells) produced by living organisms |
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Chemical sedimentary rocks |
made up of minerals that precipitate directly from water solution |
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Organic sedimentary rocks |
formed from carbon-rich relicts of organisms (i.e. coal) |
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Sedimentary rock |
rock that forms either by the cementing together of fragments broken off preexisting rock or by the precipitation of mineral crystals out of water solutions at or near the Earth's surface
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diagenesis |
all of the physical, chemical, and biological processes that transform sediment into sedimentary rock and that alter the rock after the rock has formed |
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Angular, poorly sorted grains indicate a ________ journey. Rounded, well sorted grains indicate a _______ journey. |
a) short b) long |
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What does a poorly sorted rock look like as opposed to a well-sorted rock? |
different grain sizes VS. uniform grain sized |
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Conglomerates |
very coarse-grained sedimentary rock consisting of rounded clasts. Form from gravel and pebbles in high energy environments |
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Alluvial fan |
a greatly sloping apron of sediment dropped by an ephemeral stream at the base of a mountain in arid or semiarid regions. |
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basement |
older igneous and metamorphic rocks making up the Earth's crust beneath sedimentary cover |
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basement uplift |
uplift of basement rocks by faults that penetrate deep into the continental crust |
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Six important processes in the sedimentary rock cycle |
1) physical and chemical weathering 2) erosion 3) transport 4) deposition 5) burial 6) diagenesis |
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Chemical weathering |
the process in which chemical reactions alter or destroy minerals when rock comes in contact with water solutions and/or air |
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Physical weathering |
the process in which intact rock breaks into smaller grains or chunks |
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sandstone |
Coarse-grained sedimentary rock consisting almost entirely of quartz. form from beaches or dunes |
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Shale |
Very fine-grained sedimentary rock that breaks into thin sheets. form from mud deposits inlow-energy environments |
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shale |
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sandstone |
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conglomerate |
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how are clastic sedimentary rocks generally classified? |
1) clast size 2) shape |
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Biologically mediated precipitation |
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precipitation |
the process by which atoms dissolved in a solution come together and form a solid |
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What does biologically mediated precipitation produce? |
mineralized skeletons; these condense andlithify to form biochemical sedimentary rocks. Important examples are most types of limestone. |
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Classification of chemical sedimentary rocks is primarily based upon ________ |
mineral content. An important subsetare the evaporites, including rock salt (halite) and gypsum |
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stratification |
(or bedding) the layering of rock |
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cross beds signify ________________ and can be used to indicate _______________ |
a) deposition along a slope b) paleo-wind direction |
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Five sedimentary structures |
1) bedding 2) cross bedding 3) graded bedding 4) ripple marks, dunes, and 5) mud cracks |
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evaporites |
salt deposits that form from evaporation of water |
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turbidite features |
an earthquake or storm triggers an underwater avalanche (turbidity current) that causes sediment to flow into deep water and settle |
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transgression |
sea level rises and floods the near-shore environment |
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regression |
sea level falls and the shoreline migratestoward the water |
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chalk |
made up of plankton shells (microscopicmarine organisms) |
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Halite |
aka "salt". Its chemical name is sodium chloride and a rock composed primarily of halite is known as "rock salt". forms in arid climates where ocean water evaporates. |
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Gypsum |
an evaporite mineral most commonly found in layered sedimentary deposits in association with halite, anhydrite, sulfur, calcite and dolomite. the most common sulfate mineral. |
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Half-life |
the time it takes for half of a group of a radioactive element's isotopes to decay |
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examples of low energy environments |
1) Floodplains, 2) lagoons, 3) mudflats, 4) deltas, 5) deep-water basins. |
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Thick sequences of sediments can be deposited as....
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sea levelrises and falls
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TerrestrialDepositional Environments
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1) Glacial till 2) mountain stream 3) alluvial fan 4) Sand dunes 5) stream channel 6) lake beds |
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Marine Sedimentary Depositional Environments
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shallow marine,deep marine
1) continental shelf 2) abyssal fan 3) abyssal plain 4) submarine canyon |
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4 dominant features that make up limestone
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1) calcite,
2) coal from organic matter, 3) shale from clay, and 4) sandstone from quartz grains. |
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Where do thick piles of sedimentary rocks accumulate?
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sedimentary basins
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Sedimentary basins |
regions where thelithosphere subsides // a depression, created as a consequence of subsidence, that fills with sediment |
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subsidence |
the vertical striking of the Earth's surface in a region, relative to a reference plane |
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Metamorphism |
changes in a rock that result in the formation of a metamorphicmineral assemblage and/or metamorphic texture |
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Protolith |
the original rock from which a metamorphic rock formed (can be of any type) |
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4 phenomena that induce metamorphism |
1) heat, 2) pressure, 3) differential stress, and 4) chemical interaction. |
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What can add heat which metamorphoses a rock?
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burial depth or contact with hot water.
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What increases pressure that metamorphoses a rock? |
depth
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What brings about differential stress that metamorphoses a rock?
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arises at fault zones and over broad regions during mountain building.
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5 metamorphic effects |
1) re-crystallization,
2) phase changes, 3) metamorphic reactions(neocrystallization), 4) pressure solution, and 5) plastic deformation. |
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Foliation |
involves the development of parallel alignment of mineral grains of preferred mineral associations (compositional banding).
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Low temperatures lead to ________ metamorphic rockswhile high-temperature create ______ metamorphicrocks |
a) low grade b) high grade |
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What can the collection of minerals in a metamorphic rock tell you? |
the temperature and pressure conditions under which thatrock formed |
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Does a rock melt during solid-state transformation? |
no; atomsrearrange into a new crystal structure
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Metamorphic foliation |
Texture with parallel surfacesor layers that develop on arock due to metamorphicprocesses |
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Recrystallization |
Changes the shape and size of grains (crystals) withoutchanging the type of mineral. Same mineral, new texture.
EXAMPLE: Limestone ---> Marble |
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Phase Change |
Transforms one mineral into another that has the samechemistry but different crystal structure (polymorph). New mineral (same chemistry), new texture. |
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Neocrystallization (new crystal) |
New minerals form that are chemically and structurallydifferent from the protolith minerals. New mineral, new texture.
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Pressure solution |
The edges of grains dissolve in water when the grains aresqueezed together, and the dissolved chemicals migrate toa new location and crystallize. New and old minerals, new texture
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Plastic deformation |
A rock is squeezed in a high temperature and highpressure environment, causing the grains to behave likesoft plastic and change shape. Same minerals, new texture. |
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Deformation |
(change in shape)-- Compression and shearforces causes rocks to change texture/grains to change shape |
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Compression |
application of force that squeezes a material; vertical or horizontal |
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Shear |
movement of one part of a material sidewaysrelative to the rest of the material |
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Metamorphic facies |
the collection of minerals (assemblage) that is indicative of a certain range of temperature and pressure conditions. |
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Types of Metamorphic Rocks |
1) Foliated 2) Non-foliated |
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Foliated metamorphic rocks |
Have either preferred mineral orientation or compositional banding |
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Nonfoliated metamorphic rocks |
Contain minerals that recrystallized and/or grew, but do not have foliation (banding) |
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Metamorphic foliation can be defined by one of two things....
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1) preferred mineral orientation (alignedinequant crystals) or, 2) compositional banding. |
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Preferred mineral orientation |
develops where differential stress causes the compression and shearing of a rock so that its inequant grains align parallel with each other. |
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Compositional banding |
the appearance of layers |
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The class of foliated rocks |
1) slate, 2) phyllite, 3) schist, and 4) gneiss. |
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The class of nonfoliated rocks |
1) hornfels,
2) quartzite, and 3) marble. |
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Intermediate graderocks
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metapmorphic rocks developed between high and low temperatures |
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Hornfel |
Heat-alteredrock withno foliation |
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Contact metamorphism |
the heat from an igneous intrusion bakes the rock around it (heat-only, no change in pressure) |
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Burial metamorphism |
Increasing temperature and pressure due to burial in a sedimentary basin |
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Regional metamorphism |
When one part of crust shoves over another so that rocks once near the surface end up at great depth |
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Hydrothermal metamorphism |
Water that is heated by magma at mid-ocean ridges reacts with crust to form metamorphic minerals (heat-only) |
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Shock metamorphism |
A pulse of heat and compression created by a meteorite impact changes the rocks near the impact site |
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Rocks that travel through different temperature andpressure conditions will have different ______ |
facies |
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Where does metamorphism occur, and what are the six types of metamorphism? |
Places where rocks are cooked and squeezed. 1) Contact metamorphism 2) Burial metamorphism 3) Dynamic metamorphism 4) Regional metamorphism 5) Hydrothermal metamorphism 6) Shock metamorphism |
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Vast regions of metamorphic rock are exposed on _________________ |
Precambrian shields |
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_____________ and _________ recycle igneous, sedimentary, and metamorphic rocks through thelithosphere |
Burial and uplift |
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The Rock Cycle
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How igneous, sedimentary, and metamorphic rocks are recycled in the lithosphere |
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The recycling of rocks is largely related to ________ processes but also to processes at____________ |
a) plate tectonic processes, b) the Earth’s surface (where rock meets air, water, and life) |
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Igneous rocks form at |
1) rifts, 2) subduction zones, and 3) hot spots where mantle rock melts |
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Mafic rocks form when... |
the melt comes mostly from mantle rocks |
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Felsic rocks form when... |
continental rocks are melted and cooled |
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Intermediate rocks form when... |
the melt contains both mafic and felsic components |
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Sedimentary rocks form in... |
1) low-lying regions where sediment is deposited after transport from uplifted regions (mountains), or 2) in water bodies where the minerals that make up sedimentary rocks precipitate out |
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Metamorphic rocks form... |
where crust is squashed and/or heated and/or buried |
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13 Processes that cycle rock through the lithosphere and change one rock type into another |
1) eruption 2) cooling 3) crystallization 4) weathering 5) erosion 6) deposition 7) compaction 8) lithification 9) heating 10) deformation 11) recrystallization 12) tectonic uplift 13) melting |
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Exhumation |
the process in which rocks that were once buried deep below ground become exposed at the Earth’s surface due to uplift and erosion of overlying rock |
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How was the Marcellus shale formed? |
due to burial and lithification of mud deposited on a shallow sea floor during the Devonian |
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Do all geological processes occur slowly over long time periods? |
No; some events occurrapidly over short time periods |
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How were the Channeled Scablands and giant ripple marks in eastern Washington formed? |
due to catastrophic flooding of Glacial LakeMissoula ~15 thousand years ago (ky), which drained multiple times over 2,000 years as anice dam melted and reformed multiple times |
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four major types of igneous rocks |
1) granite 2) rhyolite 3) gabbro 4) basalt |
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granite |
coarse-grained felsic rock |
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rhyolite |
fine-grained felsic rock |
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gabbro (coarse mafic) |
coarse-grained mafic rock |
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basalt |
fine-grained mafic rock |
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Geologic time |
the time span since Earth formed. |
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Relative age |
specifies whether one geologic feature is older than or younger than another |
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Numerical age |
provides the age of a rock or geologic feature in years |
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7 Principles for defining Relative Age |
1) Principle of uniformitarianism 2) Principle of original horizontality 3) Principle of superposition 4) Principle of lateral continuity 5) Principle of cross-cutting relationships 6) Principle of baked contacts 7) Principle of inclusions |
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Principle of uniformitarianism |
geologic processes and natural laws now operating to modify the Earth's crust have acted in the same regular manner and with essentially the same intensity throughout geologic time |
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Principle of original horizontality |
Sediments are deposited in flat, horizontal layers that later become lithified. Sediment accumulation is not favored on a slope |
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Principle of superposition |
In a sequence of sedimentary rock layers, each layer must be younger than the one below it. Sediment cannot accumulate unless there is a surface to accumulate on. The bottom later is the oldest, the top layer is the youngest |
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The principle of lateral continuity |
Sediments accumulate in continuous layers within a region. If you see a sedimentary layer cut by a canyon, you can assume those rocks were once connected as a continuous layer, then eroded to form the canyon. |
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Principle of cross-cutting relationships |
Younger features cut across older features. Faults, dikes, erosion, etc., must be younger than thematerial that is faulted, intruded, or eroded. In other words, you can’t cut across something that isn’tthere |
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Principle of baked contacts |
An igneous intrusion metamorphoses (bakes) the surrounding rocks, so the rock that has been baked must be older than the intrusion |
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Inclusions |
rock fragments contained within another rock |
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Principle of Inclusions |
Inclusions are always older than the material they’reenclosed in |
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The principle of fossil succession |
states that the assemblage of fossils in strata changes from base to top of a sequence. Once a species becomes extinct, it never reappears. |
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Fossils serve as useful features for marking relative age because... |
1) They are characteristic of certain environments 2) Each type of fossil only existed for a short time |
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Fossil range |
the interval over which a fossil occurs; Each fossil has a unique range |
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Index fossils |
widespread but short-lived; can be used to identify specific time periods |
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Fossil assemblage |
a group of fossil species that exist together within a rock. overlapping fossil ranges |
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Unconformities |
gaps in the rock record due to erosion and/or non-deposition |
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Three types of unconformity |
1) angular unconformity 2) Nonconformity 3) Disconformity |
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angular unconformity |
Layers (strata) below the unconformity are tilted relative to layers above the unconformity; bottom rocks tilted or folded before the unconformity occurs. Example: horizontal marine sediments are deformed by mountain building. The mountains are eroded completely away . There is a new renewed marine invasion, and new sediments deposit. |
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Nonconformity |
Sedimentary rocks overlie much older intrusive igneous and/or metamorphic rocks (basement rock). Igneous or metamorphic rocks were exposed at the surface by erosion, and new sediment was deposited on this eroded surface |
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Disconformity |
When parallel layers bound a time of non-deposition (interruption in sediment deposition). Time is missing between two layers. Often hard to recognize Example: sea level falls, then rises |
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A stratigraphic column |
shows the succession of strata in a region |
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stratigraphic formation |
A given succession of strata that can be traced over a fairly broad region |
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Correlation |
The process of determining the relationship between strata at two separate locations |
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Geologic map |
shows the distribution of formations and geologic structures |
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The geologic column |
a composite chart that represents the entirety of geologic time |
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The numerical age of rocks can be determined by ______________ dating. |
isotopic (radiometric) This is because radioactive elements decay at a rate characterized by a known half- life. |
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alternative methods for dating materials |
1) counting growth rings in trees 2) seasonal layers in glaciers |
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What does the isotopic age of a mineral specify? |
the time at which the mineral cooled below a closure temperature |
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We can use isotopic dating to determine when an igneous rock ________ and when a metamorphic rock ________. |
solidified; coolde |
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How do we date sedimentary strata? |
we must examine crosscutting relations with dated igneous or metamorphic rock |
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Based on the geologic definition of a mineral, which of the following is a mineral (or iscomposed of minerals): Molten candle wax, an asphalt shingle on a roof, sugar crystals in a sugar cube, or the ice making up a snowflake? |
the ice making up a snowflake |
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When we say that a material is “crystalline” we mean that internally… |
atoms are distributed in an orderly arrangement. |
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Which of the following minerals has a metallic luster: pyrite, halite, feldspar, or quartz? |
Pyrite |
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The chemical formula of quartz is SiO2, meaning... |
the piece contains one silicon atom for every two oxygen atoms |
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Igneous rocks that form at mid-ocean ridges have _____________ composition, whileigneous rocks that form at continent-continent collisions have _____________composition. |
mafic/felsic |
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Rocks that were buried underground are exposed at the Earth’s surface during… |
exhumation |
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Weathering and erosion are processes that lead to the formation of which rock type? |
Sedimentary rocks |
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When we say that the Redwall Limestone, exposed in the Grand Canyon, correlates withthe Monte Cristo Limestone, exposed near Las Vegas, we mean… |
both units were deposited at approximately the same time. |
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Do crystals of the same mineral have the same structure, even if they’re very different in size? |
Yes |
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Specific gravity |
represent how dense (mass/volume) a mineral is, due to how heavy and closely packed its atoms are |
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If a sample has good cleavage in three directions, and each cleavage direction is at rightangles to the other two, then . . . |
when crystals break, little cube-shaped fragments form. |
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The seven principal classes of minerals are distinguished from each other based on... |
their chemical composition |
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The fundamental unit of the most common mineral class on Earth is... |
the silicon-oxygen tetrahedron |
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Isolated tetrahedra |
No sharing of oxygen atoms (olivine, garnet): 4 silicate - 1 oxygen |
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Three-dimensional framework |
Total sharing (quartz, feldspar): 2 Si : 1 O |
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Two-dimensional sheet |
mica |
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Is quartz a single-chain silicate? |
no |
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If you find an outcrop of coarse-grained igneous rock, you are probably looking at... |
a large pluton of slowly cooled magma that formed deep in the crust |
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Fine grained rocks cooled ______ coarse grained rocks cooled _____ |
quickly; slowly |
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Biochemical limestone can consist of... |
coral mounds and/or calcite shell fragments |
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During metamorphism, a protolith.... |
undergoes change in the solid state |
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Metamorphism of sandstone produces.... |
quartzite |
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metamorphism of limestoneproduces.... |
marble |
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Application of _________________ during metamorphism causes inequant grains to align parallel to each other; when this happens, minerals in the rock develop ________________. |
differential stress/preferred orientation |
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Gneiss |
Well-developed banding due torecrystallization, original bedding,extreme shearing. Forms at high temperature/pressure |
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Shale |
low-grade; will transform to new and different metamorphic rocks with increasing temperature and pressure |
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When we say that the ruins of the Roman forum are older than the towers of Notre DameCathedral in Paris, we provide an example of... |
relative age |
